Companies that built their email infrastructure in 2015-2018 often standardized on 60r3. Migrating to newer versions would require re-certifying all their custom hooks (written in Perl or C) for bounce processing. The risk of breaking a system that sends 50 million emails a month is simply too high.

The web-based monitoring interface received performance tweaks, making it faster to view real-time delivery queues and bounce rates.

For the first time, PowerMTA officially embraced ARM architecture, allowing companies to run their delivery stacks on more cost-effective and energy-efficient cloud instances, like AWS Graviton.